Lesson video

Hello, my name is Mrs. Holbrow.

I'm so pleased you decided to join me for the lesson today.

We are gonna have so much fun making instruments, create music in Scratch.

Welcome to today's lesson from the unit programming sequence using sound.

This lesson is called ordering commands.

And by the end of today's lesson, you should be able to recognise that the order of commands in a programme affects the output.

By the output, we mean what the programme will do.

You'll need to have access to Scratch for this lesson, and it would be helpful if you had your worksheet ready.

We will be using these key words during today's lesson.

Order.

Order.

The way things are arranged in a sequence.

Notes.

Notes.

The duration and pitch of a sound.

Chord.

Chord.

Two or more notes played together at the same time.

We will be using these key words throughout today's lesson.

Okay, let's make a start with the first part of today's lesson by looking at why the order of a sequence matters.

The order of a sequence is the way commands in a programme need to be followed, one after the other.

Look carefully at these two sequences of code.

What is the difference about the order of commands in these two sequences? Does the order of the sequence matter? The end result of the sequence might not be the same if a different order is followed.

Let's take the example of tying your shoelaces.

If you didn't follow the steps in the correct order, you wouldn't tie your shoelaces correctly, and they would become undone.

Can you think of any other examples or activities where the order of a sequence matters? A computer will follow a sequence of commands precisely.

Computers are not like humans.

They will not use common sense to alter their actions.

They will only follow the commands that they are given.

The outcome of a sequence will change if the order is different.

By the outcome, we mean what the programme does.

We can see here the lady bug does not get to the strawberry because the order of commands is wrong.

The move command should come before the turn command.

Take a look at these sequences of shapes.

What should come next in each sequence? Pause your video here and have a think.

That's correct.

For the first example, the number of blue circles is increasing by two each time.

So next in the sequence would be 10 blue circles.

In the second example, the pattern of the sequence is a green square followed by a blue circle, followed by a purple triangle and then another blue circle.

So next in the sequence would be a blue circle followed by a purple triangle, a blue circle and then a green square.

Did you get the sequences right? Great job.

In music, notes are put into the order they're going to be played.

If we change the order of notes, then the sound or tune that is played will be different.

Musicians use sequences of notes to create music.

You have seen previously in Scratch that sounds can be added to a sprite.

In Scratch, each sprite has its own sound which can be played.

Take the guitar.

These are some of the sounds that this sprite can play.

To play musical notes, you need to choose a musical instrument sprite.

Here are some examples of musical instruments sprites.

Guitars, keyboard, trumpet and saxophone.

Other sprites will play sounds but not musical notes.

Fantastic listening so far.

Let's check your understanding of the sounds each sprite can play.

Each sprite has its own sound.

Which Sprite has musical notes? A.

The saxophone.

B.

The crab.

Or C.

The ballerina.

Pause your video here and have a think.

Well done.

A.

The saxophone has musical notes as it's a musical instrument sprite.

Okay, it's now time for you to have a go at an activity.

Open a new Scratch file and add any musical instrument of your choice.

Then add the following code blocks.

It's important you follow the order shown on the screen.

Pause the video here whilst you complete the task.

Now change the order of the blocks into the new order shown on the screen.

Use your worksheet to explain what happens when you change the order of the sequence.

Pause your video here whilst you complete the task.

How did you get on? What happened when you changed the sequence? You were asked to explain what happened when you changed the sequence of blocks.

Here is a sample answer.

Changing the order of the sequence changes the order that the sounds are played.

This alters the tune that is playing and creates a different sound from the original sequence.

You are doing so well.

It's now time for the second part of today's lesson.

You are now going to order notes to build a sequence.

Here are some notes from a well-known song.

Do you recognise it? Sam is asking how we could find out what this is.

Ah.

Jacob has a good idea.

He is suggesting that we put them into Scratch and play them.

We can then hear the music and we may recognise the tune.

This order of notes is actually an algorithm.

A precise set of ordered instructions.

An algorithm can be followed to complete a task.

Shall we check your understanding of algorithms? Fill in the blank to complete the sentence.

A is a precise set of ordered instructions.

Pause your video here and have a think.

That's correct.

An algorithm is a precise set of ordered instructions.

Well done.

An algorithm can be followed to create code.

On the left hand side, we have the notes in the order.

On the right hand side, we have followed this algorithm to create a sequence of code blocks in Scratch.

What do you think will happen if I run this code in Scratch? If I run this code in Scratch, it will play the notes one after another until it gets to the end.

Great listening so far.

Well done.

Time for a check.

Which note is repeated three times in this sequence? Is it option A, C guitar.

Option B, G guitar.

Or option C, A guitar.

Pause the video here and have a think.

Did you say the correct option was B, G guitar? Well done.

The G appears three times in the sequence of notes.

Now it's your turn to have a go.

Create a new Scratch project.

Choose any musical instrument sprite that you would like to use.

Remember, it has to be a musical instrument to have musical notes as sounds.

Add the sequence of code blocks shown in the order on the screen to create the first line of the song.

When you have added the code blocks, run the code.

Do you recognise the tune? Pause the video here whilst you complete the task.

Now, follow these clues to create the next line in the song.

The notes available on a Scratch musical instrument are C, D, E, F, G, A and B.

And these notes go from low to high.

You will need to use the notes F, E, F, C, D, E, D for the next line in the song but not in this order.

The notes on the second line of the song go from high to low.

The order of the notes follow a similar sequence to the first line of the song.

Can you use these clues to create the second line of the song? Pause your video here whilst you complete the task.

Excellent work.

Did you run the code and recognise the tune? That's right.

The tune was from the nursery rhyme, "Twinkle, Twinkle Little Star." You were given some clues about the next line of the song.

Did you manage to create it? The sequence of the notes for the next line of the song should have been F, F, E, E, D, D, C.

If you didn't get it quite right, perhaps pause the video here and edit your code so it plays the next line of the song correctly.

Fantastic work so far.

We are now moving on to the final part of today's lesson.

We are going to combine sound blocks to make our own music.

This Scratch project uses different events to play sounds.

Sam is asking whether we think there is something different about how each set of sounds play.

Shall we open the project and have a look? (gentle guitar music) Yes, Jacob is correct.

One set of sounds plays all at the same time.

Whereas the other set plays one after another.

Let's check your understanding of the different sound blocks.

Which code block will play one note after another? Pause your video here and have a think.

That's correct.

The right hand code block will play the sounds one after another.

This is because the play sound until done blocks have been used rather than the start sound blocks.

The start sound blocks start the notes at the same time rather than waiting for the previous note to finish.

A chord is created when two or more notes are played together at the same time.

C chord is created when the notes C, E and G are played together at the same time.

F chord is when the notes F, A and C are played together at the same time.

And G chord, when the notes G, B, and D are played together at the same time.

Which sound block would you use if you wanted to create a chord? Remember, a chord is created when two or more notes are played together at the same time.

Pause the video and have a think.

Well done.

A is the correct answer as the code block would start the sound at the same time as the other code blocks.

B is not correct as this would play the sound until it finishes before playing the next code block.

Time for you to have a go at creating your own musical project.

Open a new Scratch project.

Add the keyboard sprite and add sound blocks to create one of these chords.

C chord, F chord or G chord.

Pause your video here whilst you complete the task.

On your worksheet, answer these two questions.

Three.

Which event block did you use and why? Four.

Does the order of the notes matter? Explain why.

Pause the video here whilst you record your answers on your worksheet.

Now if you have time, add more code blocks to make multiple chords.

Each chord should be started by a different event.

Pause the video here whilst you have a go.

How did you get on? Did you manage to get your keyboard to play a chord? Here is some sample code.

See that we have used the start sound code blocks as we want the notes to all play together at the same time.

You were asked to explain which event you used and why.

Here is a sample answer.

I used the when space key pressed event block as I could then play the chord each time I press the key.

You were then asked if the order of the notes mattered.

All of the sounds are starting at the same time.

So in this case, the order of the sequence does not matter.

You have worked so hard in today's lesson, and I hoped you enjoyed creating your own music in Scratch.

Let's summarise what we have learned today.

Instrument sprites have musical notes as sounds.

Other sprites have sounds, but not musical notes.

To make music, notes should be arranged in a specific order, and the sequence is important.

Playing more than one note at the same time makes a chord.

Thank you so much for joining me in today's lesson, and I hope to see you again soon.

Bye.